November 24th, 2024

Elevated nitrate levels in Southland's water raise concerns for public health

Emerging evidence from global studies suggests potential health risks at much lower nitrate levels, including increased risks of bowel cancer and preterm birth.

The majority of New Zealanders have access to water with nitrate levels below 1 mg/L. However, around 800,000 people, mostly in rural areas, are exposed to potentially hazardous nitrate levels above 1 mg/L.
The majority of New Zealanders have access to water with nitrate levels below 1 mg/L. However, around 800,000 people, mostly in rural areas, are exposed to potentially hazardous nitrate levels above 1 mg/L.

Greenpeace Aotearoa's recent free nitrate water testing in Southland has discovered high contamination levels in Gore and Lumsden's public water supplies, as well as in surrounding rural areas.

Christine Rose, Greenpeace's lead climate and agriculture campaigner, expressed concern about samples from Gore and Lumsden showing nitrate levels greater than 4 milligrams/litre (mg/L), according to a media release issued on Friday.

Rose highlighted that nitrate levels above 5 mg/L have been linked to increased risk of preterm birth, according to a Californian study.

The majority of New Zealanders have access to water with nitrate levels below 1 mg/L. However, around 800,000 people, mostly in rural areas, are exposed to potentially hazardous nitrate levels above 1 mg/L. Greenpeace's testing programme found the highest nitrate reading, 21.5 mg/L (NO3-N), on a dairy farm in the region, nearly twice the maximum acceptable value for nitrate in drinking water.

Emerging evidence from global studies suggests potential health risks at much lower nitrate levels, including increased risks of bowel cancer and preterm birth. Greenpeace's testing in Lumsden and Gore found 65% of samples above the cancer risk level of 1 mg/L and 20% above the preterm birth risk level of 5 mg/L.

Nitrate contamination has been linked to the rise in synthetic nitrogen fertiliser use and increased dairy cow numbers over the past three decades. Greenpeace urges the government to regulate cow numbers and phase out synthetic nitrogen fertiliser and imported feed to protect public health and communities.